LET’S TAKE THE LONG WAY HOME, a shimmeringly lovely second memoir from former Boston Globe books editor GAIL CALDWELL, opens with this brutally heartbreaking sentence: “It’s an old, old story: I had a friend and we shared everything, and then she died and we shared that too.” Caldwell, an Amarillo native and University of Texas graduate, provokes tears and laughter (and remembers her own) as she parses the singularity of her friendship with Caroline Knapp, the author of the acclaimed Drinking: A Love Story, who died in 2002, seven weeks after being diagnosed with lung cancer. She was 42. The pair first bonded in the mid-nineties like twins separated at birth: determined dog owners training new puppies on marathon ambles, obsessive exercisers rowing sculls on Boston’s Charles River, recovering alcoholics who shared a near-paralyzing shyness. Their need for companionship and mutual approval transcended work, play, family, and even boyfriends, but Caldwell’s celebration of their camaraderie can’t disguise her grief at Knapp’s death. Random House, $24